822 



THE OKGANS OF SENSE. 



sebaceous glands, named the tarsal glands. The superior tarsus is larger than 

 the inferior, and of a half oval shape, with its greatest vertical diameter measuring 

 about 10 or 11 mm. Its upper margin is thin and convex, and is continuous with 

 the tendon of the levator palpebrse superioris muscle, while its lower edge is thick 

 and straight. The inferior tarsus is a thin, narrow strip, with a nearly uniform 

 vertical diameter of about 5 mm. The extremities of the two plates are con- 

 tinuous with the lateral palpebral raphe and the medial palpebral ligament. The 

 lateral palpebral raphe is a narrow band attached to the zygomatic bone ; it divides, 

 at the lateral commissure, into superior and inferior pieces which are fixed to the 

 margins of the respective tarsi. The medial palpebral ligament is a strong band 

 attached to the frontal process of the maxilla, directly in front of the lacrimal 



Tendon of levator palpebrse 

 superioris 



Conjunctiva 



Tarsal gland in tarsus 



Muscle of Riolan 



Skin 



Orbicularis oculi 



Eyelashes 



FIG. 698. SAGITTAL SECTION THROUGH SUPERIOR EYELID. 



groove ; it divides at the medial commissure into two slips, one for each tarsus 

 (Fig. 699). 



The eyelids are further strengthened by membranous expansions, termed the 

 superior and inferior palpebral ligaments, which extend into them from the margin 

 of the orbit. The superior palpebral ligament is continuous, along the superior 

 margin of the orbit, with the pericranium and with the periosteal lining of the orbit, 

 and it blends, below, with the tendon of the levator palpebrse superioris. The inferior 

 palpebral ligament is prolonged from the lower edge of the inferior tarsus to the 

 inferior margin of the orbit, where it is continuous with the periosteum of the face 

 and orbital floor. Laterally the two palpebral ligaments fuse to form the lateral 

 palpebral raphe, while medially they become thinned, and, separating from the 

 medial palpebral ligament, are attached to the lacrimal bone, behind the lacrimal 

 sac. The superior and inferior palpebral ligaments form the septum orbitale, between 

 the superficial and deep structures of the eyelids ; this septum is perforated by the 

 vessels and nerves, which extend from the orbital cavity to the face or scalp. 



